Quaternary ammonium compounds have been widely used as bactericides, algicides and molluscicides to treat circulating or static bodies of water. These compounds are used in the water treatment of cooling towers, pool, and spa industries. The traditional quaternary amine compounds are of the higher alkyl and dialkyl variety.
Some of their disadvantages are limited spectrum of biocidal activity, high foaming characteristics, inherent toxicity, disagreeable odor production, and inhibited use in hard water. U.S. Pat. Nos. 4,444,790; 4,450,174; 5,015,395 reveal some of the background. U.S. Pat. No. 5,290,805 describes the use of decyl (nonyl)-and decyl/isononyl dimethyl ammonium chloride compounds which do not have these problems. Other quatemary amines that have been used as biocides are: didecyl dimethyl ammonium chloride (trade name Bardac 2250, Lonza); N-alkyl (C14-50%; C12-40%; C16-10%) dimethyl benzyl ammonium chloride (Barquat MB50, Lonza); Diisodecyl dimethyl ammonium chloride (BTC 99, Stepan); poly (oxyethylene ((dimethylimino)) ethylenedimethyl imino ethylene dichloride; Buckman WSCP). N-Alkyl (C14, 95%; C12, 3%; C16-2%) dimethyl benzyl ammonium chloride (Bio-Quat 50-28, Bio-Lab).
The amount of quatemary compounds that are used in water depend on the particular application. In pools, spas and other stationary bodies of water, the amount of quatemary amine dissolved in water is broadly between about 0.5 and 10 ppm. In circulating bodies of water such as recirculating cooling towers, air washers, and once through cooling systems, the concentration of quaternaries is as high as 100 ppm. The pH of the water should be between 4 and 10.
Oswald, in U.S. Pat. No. 4,188,380, describes organically modified clays where the modifier is a higher dialkyl phosphonium salt, which has biocidal properties. Another U.S. Pat. No. 4,929,644, describes blending a standard organoclay modified with di-methyl di-hydrogenated tallow ammonium chloride with another organoclay modified with a biocidal quatemary amine of the type di-methyl di-hydrogenated tallow benzyl ammonium chloride. The first organoclay imparts thickening properties to cosmetic compounds, while the second one adds biocidal activity. Neither patent suggests modifying the quaternary amine itself while preparing the organoclay.
Another type of bactericide or biocide are iodine impregnated resins. The iodine/resin disinfectant may be used to sterilize a fluid such as water or air. The disinfectant is used to devitalize microorganisms such as bacteria and viruses, which may be present in the fluid (e.g. water, air, pus, and the like). U.S. Pat. No. 5,639,452 and numerous others teach iodine/resin disinfectants obtained by contacting a strong base anion exchange resin with a suitable source of tri-iodide ions.
The terms "tri-iodide", "tri-iodide ions" and the like, as used in the context herein, refer to or characterize a substance or a complex containing three iodine atoms and which has a valence of -1. The tri-iodide ion herein therefore is a complex ion which may be considered as comprising molecular iodine (i.e. iodine as I2) and an iodine ion (i.e. I--). Similarly, the terms "poly-iodide", "poly-iodide ions" and the like, refer to or characterize a substance or a complex as having three or more iodine atoms and which may be formed if more of the molecular iodine combines with the mono-valent tri-iodide ion. These terms are more particularly described in the above referred U.S. Patents. U.S. Pat. No. 5,639,452 teaches a process comprising contacting a porous strong base ion exchange resin in a salt form other than the iodide form I-- with a sufficient amount of an iodine substance absorbable by the anion exchange resin such that the anion exchange resin absorbs said iodine-substance so as to convert the anion exchange resin to the disinfectant-resin, said iodine substance being selected from the group comprising poly-iodide ions having a valence of -1, being absorbed by the anion exchange resin. This process takes place through several conversion steps at 100 degrees C., up to 210 degrees C., and elevated pressure up to 100 psig.
The anion exchange resin may be in the hydroxyl form OH-- or chloride form Cl--, and is contacted with a composition comprising a mixture of Kl, I2 and a minor amount of water, the mole ratio of Kl to I2 initially being about 1.
Anion exchange resins are very expensive. Given the elaborate conversion process required to create iodinated resins, the price per pound is so high as to price the product out of industrial markets.
It has been found that no patents exist for the manufacture of such disinfectants using substrates other than resins. Prior art in the manufacture of organically modified clays (from hereon called organoclays) shows that quatemary amines with biocidal properties have been in use for many years. However, applicant found it possible to combine organoclays with biocidal quatemary amines and iodine compounds, to manufacture granules of such clays and to place them into a cartridge. When water with bacteria was passed through the cartridge, essentially all bacteria were killed.